ORIGINAL ARTICAL Correlation between the intima-media thickness and Framingham risk score in patients with sleep apnea syndrome Cengiz Özdemir¹, Işık Conkbayır², Aslıhan Kuru², Hikmet Fırat³, Sinem Nedime Sökücü¹, Levent Dalar¹, Recai Ergün³, Çağla Pınar Uzunmehmetoğlu³, Dilek Ergün4, Sadık Ardıc³ 1

Yedikule Chest Disease and Thoracic Surgery Education and Research Hospital, Sleep Laboratory, İstanbul, Turkey; ²Department of Radiology, ³Department of Chest Diseases, Diskapi Yildirim Beyazit Education and Research Hospital, Ankara, Turkey; 4Occupational Disease Hospital, Department of Chest Diseases, Ankara, Turkey

ABSTRACT

KEYWORDS

Background: In the present study, we want to demonstrate the correlation between obstructive sleep apnea syndrome (OSAS) whose independent effect on carotid artery intima-media thickness (IMT) was demonstrated, with Framingham risk score (FRS) showing the overall cardiovascular risk. Methods: IMT of the carotid artery was measured with ultrasonography and 10-year risk of coronary heart disease (CHD) was defined with FRS in 90 consecutive patients referred to our sleep clinic and who underwent polysomnography (PSG), with vascular risk factors and without a clinical atherosclerotic disease. Results: IMT and FRS were found to be statistically significantly increased in the severe OSAS group compared to the other two groups. Carotid IMT was found to be significantly positively correlated with, apnea-hypopnea index (AHI), oxygen desaturation index (ODI) and time duration with oxygen saturation (SpO2) 140/90 mmHg. The people who regularly smoked for the last two months were considered as smokers. The people who received oral antidiabetic drugs or insulin therapy, and those diagnosed with

Laboratory work-up

Polysomnography (PSG) With polysomnographic recording, EEG, EOG, chin EMG and bilateral anterior tibial muscle EMG, ECG, nasal airflow, respiratory effort (thorax and abdomen movements), oxygen saturation (from fingertip), tracheal microphone and body position recordings were obtained using Compumedics E-series (Compumedics, Australia). The data were collected in PSG recording system and evaluated by a single physician trained on sleep disorders and PSG who was unaware of measurements. In the polysomnographic records, sleep stages were evaluated according to Rechtschaffen and Kales criteria with 30-second epochs. Apnea was accepted as the pause in breathing lasting for at least ten seconds and hypopnea was accepted as a 30% (or greater) reduction in flow lasting for ten seconds or longer and an associated 4% (or greater) desaturation in the oxygen levels, or if it results in arousal or fragmentation of sleep. Apneahypopnea index (AHI) was taken as the number of apneas and hypopneas per hour and oxygen desaturation index (ODI) as the number of decrease in desaturation >4% per hour of sleep. In addition, T90 which is the percentage of the total sleep time with oxygen saturation below, mean oxygen saturation (mean SpO2) and minimum oxygen saturation at sleep (min SpO2) were recorded. Severity of OSAS was defined according to AHI. An AHI of 5 to15 is classified as mild obstructive sleep apnea; 15 to 30 is moderate OSA; 30 or more is severe OSA. Carotid artery IMT measurement Gray scale and color doppler sonography of the bilateral carotid arteries was performed using a SSA-390A Power Vision 8000 scanner (Toshiba, Tokyo, Japan) equipped with a 6-11 MHz linear-

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Journal of Thoracic Disease, Vol 5, No 6 December 2013

Table 1. Comparison of demographic and clinic features of the groups. Features n

Control

Mild-moderate OSAS

Severe OSAS

20

35

35

P

Age (years)

41.8±5.1

44.5±6.6

46.9±6.3

0.016º

Male n, (%)

15, (75%)

32, (91.4%)

33, (94.3%)

0.106

BMI (kg/m²)

29.0±5.1

29.5±3.5

33.1±4.4

0.05, group 1-3, P0.05; ¹group 1-2, P>0.05, group 1-3, P